The ShadowBrokers, an entity previously confirmed by The Intercept to have leaked authentic malware used by the NSA to attack computers around the world, today released another cache of what appears to be extremely potent (and previously unknown) software capable of breaking into systems running Windows. The software could give nearly anyone with sufficient technical knowledge the ability to wreak havoc on millions of Microsoft users.

The leak includes a litany of typically codenamed software “implants” with names like ODDJOB, ZIPPYBEER, and ESTEEMAUDIT, capable of breaking into — and in some cases seizing control of — computers running version of the Windows operating system earlier than the most recent Windows 10. The vulnerable Windows versions ran more than 65 percent of desktop computers surfing the web last month, according to estimates from the tracking firm Net Market Share.

The crown jewel of the implant collection appears to be a program named FUZZBUNCH, which essentially automates the deployment of NSA malware, and would allow a member of agency’s Tailored Access Operations group to more easily infect a target from their desk.

According to security researcher and hacker Matthew Hickey, co-founder of Hacker House, the significance of what’s now publicly available, including “zero day” attacks on previously undisclosed vulnerabilities, cannot be overstated: “I don’t think I have ever seen so much exploits and 0day [exploits] released at one time in my entire life,” he told The Intercept via Twitter DM, “and I have been involved in computer hacking and security for 20 years.” Affected computers will remain vulnerable until Microsoft releases patches for the zero-day vulnerabilities and, more crucially, until their owners then apply those patches.